The present invention is a further development of the subject matter shown in my previous U.S. Pat. Nos. 3,589,431 and 3,730,250. These patents disclose a turntable to rotate the mold boxes between various stations during the preparation procedure. These patents show five stations, with station one for cleaning the mold boxes of sand and pattern placement; station two, a sand filling station; station three, pattern removal; station four, core insertion; and station five, mold ejection. In the present invention a new station three is added between existing stations two and three and in which hot air or catalytic or activator gas is added to react with the binder in the sand pre-mix to decrease the hardening time.
Various sand pre-mixes have in recent years become available which contain a variety of binders, catalysts, and activators which have rapid curing times and produce molds of greater dimensional accuracy, compression strength and stability so that high quality castings can be prepared. The present invention provides a method and apparatus for utilizing these mixes in an automated sequence and improved apparatus for transfer of sand to the form boxes.